The only way to stop at the last or any other arbitrary frame, i.e not the first one that we use with the built-in "rotate once" option, via auto-play is to use our API (programming interface).

For example, you can create an image label at the last frame under Images->Rows in SpotEditor (double click on an image and enter the name of a label) and then trigger the auto-play by calling our API's images.playToLabel("label name") in your javascript.